The structural gene for yeast cytochrome C.

Abstract

The primary structure of iso-1 -cytochrome c from baker''s yeast is coded by the chromosomal gene CY1. This conclusion was reached by isolating a revertant, CY 1-2-a, from a mutant strain cy1-2 that specifically lacks iso-1-cyto chrome c. The sites of the original mutation and of the reversion are at the same genetic locus, and the revertant gene segregates from the wild-type gene in the expected 2 : 2 Mendelian fashion. The structure of the iso-1-cytochrome c isolatedfrom the revertant strain differs from that of the parental protein in the heme peptide region. This was shown by amino acid analyses of the intact proteins and the heme peptides, as well as by peptide maps of tryptic and chymotryptic digests. These results indicate that mitochondria do not contain all the genetic information coding for the primary structures of all intramitochondrial proteins.